In accordance with the prior art, communication equipment, e.g. telephone and facsimile machines, usually use extended lines to transmit signals to each other. Further, the local area network (LAN), e.g. computers set up in a company, also need extended lines to transmit signals between the computers. Therein, due to the disposition of the communication equipment, the extended lines are usually too long so that portions of the extended lines are left disorderly on the ground or gathered beside tables. It is not only messy and unsightly but also wastes space. Moreover, the lengthy extended wire malfunctions easily due to improper pulling and dragging. Hence, the lengthy extended wire should be further arranged, e.g. employing a wire winding box to wind the redundant portion, to keep the environment orderly and keep the communication equipment functioning well. 
The conventional wire winding box as shown in FIG. 1 is a prior invention of the inventor of the present invention that is patented in Taiwan with serial number 395403. It includes a bottom cover 10′, rotating disk 20′, spiral spring 30′, stopping base 40′, control button 50′ and upper cover 60′, Therein, the bottom cover 10′ has a disk tank 12′ formed in its center, a containing tank 14′ and fixing tank 16′. The spiral spring 30′ is disposed in the containing tank 14′ and the control button 50′ is disposed in the fixing tank 16′. The rotating disk 20′ is disposed in the disk tank 12′ of the bottom cover 10′. The stopping base 40′ is disposed in a circular containing portion 22′  formed in the center of the rotating disk 20′ and is used to wind a wire A. The upper cover 60′ is disposed on the bottom cover 10′. 
While the wire A is pulled out, the spiral spring 30′ will also be pulled out by the circular containing portion 22′. Due to the interaction of stopping blocks 24′ formed in the periphery of the rotating disk 20′ and a projective block 56′ of the control button 50′, the rotating disk 20′ is restricted to rotate in a single direction only. While the control button 50′ is pressed to make the projective block 56′ release the stopping blocks 24′of the rotating disk 20′, the spiral spring 30′ will retract back to the containing tank 14′ and simultaneously make the rotating disk 20′  wind the wire A. 
In the conventional wire winding box mentioned above, except the disk tank, the bottom cover has the containing tank and fixing tank disposed thereon to contain the spiral spring and control button, respectively. The containing tank and fixing tank will waste space and make the volume of the wire winding box increase. 
Accordingly, as discussed above, the conventional wire winding box still has some drawbacks that could be improved. The present invention aims to resolve the drawbacks in the prior art. 